According to the U.S. Pat. No. 4,687,239, the action of the door lock is first to turn around the rotating shell 3 so as to enable the hook 32 on the rotating shell to hook on or release from the notch 41 of the extending shell 4, so that the extending shell 4 can be moved or fixed still. The parts used in the patent are so numerous that many molds are needed for its manufacture. In addition, the adjustment of the dead bolt is not so simple. Later on, the same inventor filed an application of the U.S. Ser. No. 920,673, a modified adjusting structure on the U.S. Pat. No. 4,687,239.